Reaction system and products therefrom

ABSTRACT

A reaction system and method for removing heteroatoms from oxidized-heteroatom-containing hydrocarbon streams and products derived therefrom are disclosed. An oxidized-heteroatom-containing hydrocarbon feed is reacted in a reaction system thereby forming non-ionic hydrocarbon products. The products derived therefrom are useful as transportation fuels, lubricants, refinery intermediates, or refinery feeds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application claiming the priority andbenefit of U.S. application Ser. No. 12/888,049, filed Sep. 22, 2012,entitled “Reaction System and Products Therefrom.”

BACKGROUND

The present disclosure is directed to systems and methods for treatingcrude oil, intermediate refining streams, and refining products tosubstantially reduce the content of undesired heteroatoms, specificallysulfur, nitrogen, nickel, vanadium, iron and reduce the total acidnumber and to do so utilizing equipment that has a relatively lowcapital investment and is economical to operate.

Systems and methods for removing oxidized-heteroatom contaminantsincluding, but not limited to, sulfur, nitrogen, nickel, vanadium, ironand reduce the total acid number of liquid hydrocarbon feed streams aredisclosed. After subjecting a liquid hydrocarbon stream to oxidationconditions, thereby oxidizing at least a portion of the heteroatomcompounds (e.g., oxidizing dibenzothiophenes to sulfones), the oxidizedheteroatom compounds are reacted with caustic (e.g., sodium hydroxide,potassium hydroxide, eutectic mixtures thereof etc.) and a selectivitypromoter to produce substantially lower heteroatom-containinghydrocarbon products.

As is well known in the industry, crude oil contains heteroatoms such assulfur, nitrogen, nickel, vanadium and acidic oxygenates in quantitiesthat negatively impact the refinery processing of the crude oilfractions. Light crude oils or condensates contain heteroatoms inconcentrations as low as 0.001 Wt %. In contrast, heavy crude oilscontain heteroatoms as high as 5-7 Wt %. The heteroatom content of crudeoil increases with increasing boiling point and the heteroatom contentincreases with decreasing API gravity. These impurities must be removedduring refining operations to meet the environmental regulations for thefinal product specifications (e.g., gasoline, diesel, fuel oil) or toprevent the contaminants from decreasing catalyst activity, selectivity,and lifetime in downstream refining operations. Contaminants such assulfur, nitrogen, trace metals, and total acid number (TAN) in the crudeoil fractions negatively impact these downstream processes, and others,including hydrotreating, hydrocracking and FCC to name just a few. Thesecontaminants are present in the crude oil fractions in varyingstructures and concentrations.

It is widely recognized that the emission of sulfur oxides from fossilfuel combustion causes a serious atmospheric pollution problem. Indeed,the sulfur is converted through combustion into various sulfur oxidesthat can be transformed into acids, thus, it is believed, SO_(x)emissions contribute to the formation of acid rain and also to thereduction of the efficiency of catalytic converters in automobiles.Furthermore, sulfur compounds are thought to ultimately increase theparticulate content of combustion products.

A variety of methods have been proposed for removing sulfur compoundseither from fuels before combustion or from emission gases afterward.Most refineries employ hydrodesulfurization (HDS) as the predominantprocess for removing sulfur from hydrocarbon streams. HDS remains acost-effective option for light streams with sulfur levels up to about2% (w/w) elemental sulfur. But the environmental benefits of HDS areoffset in very heavy and sour (>2% elemental sulfur) streams because theenergy input to the reaction, the high pressures and the amount ofhydrogen necessary to remove the sulfur paradoxically create asubstantial CO₂ emission problem.

Because of these issues, reduction of contaminants and, in particular,of the sulfur content in hydrocarbon streams has become a majorobjective of environmental legislation worldwide. Pending sulfurregulations in the United States for on-road diesel will be 15 ppm inNRLM diesel fuel. By October 2012, on road diesel sulfur specificationswill be 15 ppm for NRLM diesel fuel. In the European Union thatspecification is expected to tighten to 10 ppm in January 2011 fordiesels intended for inland waterways and for on-road and off-roaddiesel operated equipment. In China, the on-road diesel specificationwill be 10 ppm by 2012. Currently the tightest specifications in theworld are in Japan, where the on-road diesel specification is 10 ppm.

Refiners typically use catalytic hydrodesulfurizing (“HDS”, commonlyreferred to as “hydrotreating”) methods to lower the sulfur content ofhydrocarbon fuels. In HDS, a hydrocarbon stream that is derived from apetroleum distillation is treated in a reactor that operates attemperatures ranging between 575 and 750.degree. F. (.about.300 to.about.400.degree. C.), a hydrogen pressure that ranges between 430 to14,500 psi (3000 to 10,000 kPa or 30 to 100 atmospheres) and hourlyspace velocities ranging between 0.5 and 4 h.sup.-1. Dibenzothiophenesin the feed react with the hydrogen when in contact with a catalystarranged in a fixed bed that comprises metal sulfides from groups VI andVIII (e.g., cobalt and molybdenum sulfides or nickel and molybdenumsulfides) supported on alumina. Because of the operating conditions andthe use of hydrogen, these methods can be costly both in capitalinvestment and operating costs.

As is currently known, HDS or hydrotreating may provide a treatedproduct in compliance with the current strict sulfur level targets.However, due to the presence of sterically hindered refractory sulfurcompounds such as unsubstituted and substituted dibenzothiophenes, theprocess is not without issues. For example, it is particularly difficultto eliminate traces of sulfur using such catalytic processes when thesulfur is contained in molecules such as dibenzothiophene with alkylsubstituents in position 4, or 4 and 6. Attempts to completely convertthese species, which are more prevalent in heavier stocks such as dieselfuel and fuel oil, have resulted in increased equipment costs, morefrequent catalyst replacements, degradation of product quality due toside reactions, and continued inability to comply with the strictestsulfur requirements for some feeds.

This has prompted many to pursue non-hydrogen alternatives todesulfurization, such as oxydesulfurization. One attempt at solving thethiophene problem discussed above includes selectively desulfurizingdibenzothiophenes contained in the hydrocarbon stream by oxidizing thedibenzothiophenes into a sulfone in the presence of an oxidizing agent,followed by optionally separating the sulfone compounds from the rest ofthe hydrocarbon stream. Oxidation has been found to be beneficialbecause oxidized sulfur compounds can be removed using a variety ofseparation processes that rely on the altered chemical properties suchas the solubility, volatility, and reactivity of the sulfone compounds.One specific sulfoxidation method and system is disclosed inInternational Publication Number WO 2009/120238 A1, to Litz et al., thedisclosure of which is hereby incorporated by reference to the extentnot inconsistent with the present disclosure.

One issue with sulfoxidation lies in the disposal of the sulfones. Ifthe sulfones are hydrotreated, they may be converted back to theoriginal dibenzothiophene compounds thereby regenerating the originalproblem. The feed sulfur content may be likely to be in the range of 0%to 10% weight sulfur. Sulfur, on average, comprises about 15 wt % ofsubstituted and unsubstituted dibenzothiophene molecules. Therefore, upto 67 wt % of the oil may be removed as sulfone extract. For a typicalrefinery processing 40,000 barrels per day of crude oil, up to 27,000barrels per day of sulfone oil will be generated, which is believed tobe too much to dispose conventionally as a waste product. Further, thedisposal of sulfone oil also wastes valuable hydrocarbons, which couldtheoretically be recycled if an efficient process were available.

As stated above, the primary challenge presented to oxydesulfurizationremains the removal of the SO_(x) from the sulfone and sulfoxide groupscreated by oxidation of the initial organic sulfur species. Kocal etal., U.S. Pat. No. 7,790,021 B2, the disclosure of which is herebyincorporated by reference to the extent not inconsistent with thepresent disclosure, teach the use of an aqueous caustic stream and acaustic waste stream to treat the sulfones and sulfoxide streams toproduce substituted biphenyls. The problem with the disclosed method isthe costly extra steps to remove the substituted biphenyl products fromthe aqueous caustic stream and the lack of selectivity towardsunsubstituted biphenyls, and the lack of teaching any effect on otherheteroatom-containing species.

A similar teaching of the use of molten caustic was disclosed by Aida etal (reference) to treat the sulfones in oxidized coal. Aida's teachinggives rise to ionizable and non-ionizable biphenyls with no apparentselectivity to product formation. Aida later teaches (TetrahedronLetters publication) that desulfonylation with caustic alkoxide ionsproceeds with predominant formation of carbon oxygen bond formation butstill substantive formation of hydroxybiphenyls which are extremelychallenging to separate from the caustic stream because they areionizable.

Garcia et al (J. Mol Catalysis 2008) teach a desulfonylation reactioncatalyzed by nickel compounds. Aida and Kocal et al. showed thatcaustics react with sulfones, but their methods do not show selectivityto unsubstituted products and has not been shown capable of removingother heteroatoms. Garcia et al. show that there is a way to selectivelymake unsubstituted biphenyls from sulfones, but fail do so in a costeffective manner and they do not demonstrate the capability of removingother heteroatoms. The method unfortunately employs an expensivestoichiometric Grignard reagent to selectively form unsubstitutedbiphenyl products and is therefore unsuited to commercial fuel treatmentfor economic reasons.

Documents and references believed relevant to the present disclosurefollow:

Reaction of Dibenzothiophene Sulfone with Alkoxides Aida, T.; Squires,T. G.; Venier, C. G. Tetrahedron Letters, (1983), 24(34) p 3543-3546

Development of an efficient coal-desulfurization process:oxy-alkalinolysis Authors Aida, T.; Venier, C. G.; Squires, T. G.

-   Publication Date 1982 Sep. 1 Technical Report Resource Conference:    American Chemical Society symposium on coal liquefaction, pages    328-334 Kansas City, Mo., USA, 1 Sep. 1982 Ames Lab., IA (USA);    Advanced Fuel Research, Inc., East Hartford, Conn. (USA)-   Deoxydesulfurization of Sulfones Derived from Dibenzothiophene using    Nickel Compounds, Authors: Alberto Oviedo, Jorge Torres-Nieto, Alma    Arevalo, and Juventino J. Garcia. J. Mol. Catalysis A:    Chemical, (2008) 293, p 65-71.

It has long been known that various metallic elements are found innaturally occurring and synthetic crude oils (see O. I. Miller et al,Anal. Chem., 24, 1728 [1952]).

Some of these metal impurities are known to be harmful when present incharge stocks for petroleum refining, for example cracking, when presentin fuels for boilers and turbines and the like uses.

A process for removing vanadium and sodium from a crude oil is disclosedin U.S. Pat. No. 2,764,525 (F. W. Porter et al) wherein the oil iscontacted in the presence of hydrogen with alumina containing a minoramount of ferric oxide.

A method of treating petroleum oil containing trace metal components isdisclosed in U.S. Pat. No. 2,910,434 (H. V. Hess, et al) wherein the oilis contacted with an inert packing material in the presence of hydrogengas.

In U.S. Pat. No. 2,987,470 (M. Turken) a process is disclosed fordemineralizing oil by contact thereof in an ebullated bed withparticulate contact materials, for example bauxite, alumina and thelike.

In U.S. Pat. No. 3,819,509 (R. H. Walk et al) metal- andsulfur-containing contaminants in a residual oil are removed from theoil by contacting the oil in the presence of desulfurization catalystand an intimate admixture of inert demetallization solids.

In U.S. Pat. No. 3,964,995 (R. H. Walk et al) metals are removed fromsulfur- and metals-contaminated oil using porous alumina solidsactivated with an oxide promoter of the group Fe₂O₃, TiO₂ and SiO₂.

In U.S. Pat. No. 4,192,736 (Kluksdahl) metals are removed from oil bycontact with alumina containing a phosphorous oxide promoter.

In U.S. Pat. No. 4,645,589 (F. J. Krambeck et al) metals are removedfrom oil by aqueous phase extraction with a phosphorous compound.

A process for removing metals and coke precursors is disclosed in U.S.Pat. No. 6,245,223 (M. L. Gorbaty et al) wherein the oil is contactedwith a solid, low surface area adsorbent.

Therefore, there is a need for a selective process for removingheteroatoms (including, but not limited to, sulfur, nitrogen, nickel,vanadium, iron and the like) from an oxidized-heteroatom-containinghydrocarbon stream thereby avoiding the need of expensive reagents,waste disposal, and other separation and handling as well as cost issuesassociated with the waste streams.

The inventors of the present disclosure have unexpectedly discoveredthat the removal of heteroatoms from substantiallyoxidized-heteroatom-containing hydrocarbon streams may be promoted byemploying the novel reaction system detailed herein. What we hereindisclose are systems and methods for showing selectivity towardnon-ionic hydrocarbon products employing a novel caustic reactionsystem. Not only have we learned that our reaction system functions forsulfur removal but we also have learned that it has a beneficialcapability of removing nitrogen, trace metals and reducing the totalacid number of a hydrocarbon fuel and increasing the API gravity.

SUMMARY OF THE DISCLOSURE

A reaction method and system for decreasing the heteroatom content,decreasing the total acid number, and increasing the API gravity from asubstantially oxidized-heteroatom-containing hydrocarbon feed stream,including, but not limited to, internal refinery streams, crude oil ordistilled fraction of crude oil is disclosed. The reaction system may bepresently preferably heated and may comprise a feed inlet region, areaction region and an outlet region; the reaction region may comprise acaustic compound, optionally a mixture of caustic compounds, andoptionally supported on an inert metal oxide, and a molten causticliquid, and optionally a molten caustic mixture; the inlet regionreceives the feed independently or as a mixture comprising aoxidized-heteroatom-rich hydrocarbon and a selectivity promoter thatcombine to contact with the caustic compound(s); wherein theoxidized-heteroatom-rich hydrocarbons react with the caustic andselectivity promoter producing substantially non-ionic hydrocarbonproducts that exit via the outlet region with a lower heteroatom contentthan the feed.

The caustic component of the reaction region of the system of thepresent disclosure may be any inorganic compounds that exhibit basicproperties; presently preferably inorganic oxides from group IA and IIAelements; more presently preferably inorganic hydroxides from group IAand IIA elements, or optionally mixtures of oxides and hydroxides ofgroup IA and IIA elements; even more presently preferably moltenhydroxides of group IA and IIA elements, or optionally mixtures ofhydroxides of said elements; and presently most preferably molten NaOH,KOH, or a mixture thereof. Non-limiting examples may include, but arenot limited to, Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, Fr₂O, BeO MgO, CaO, SrO,BaO, and the like as well as LiOH, NaOH, KOH, RbOH, CsOH, FrOH, Be(OH)₂,Mg(OH)₂, Ca(OH)₂, Sr(OH)₂, Ba(OH)₂, and the like, and their mixtures ormolten mixtures thereof.

The optional support components of the reaction region of the reactionsystem of the present disclosure may be any inorganic oxide, eitherinert or active; in particular a porous support such as talc orinorganic oxides may be utilized as support components.

Suitable inorganic oxides may be oxides of elements of groups 2, 3, 4,5, 13, 14, 15 and 16 of the Periodic Table of the Elements. Examples ofoxides preferred as supports may include silicon dioxide, aluminum oxideand also mixed oxides of the two elements and corresponding oxidemixtures. Other inorganic oxides which may be used alone or incombination with the abovementioned preferred oxide supports may be, forexample, MgO, ZrO₂, TiO₂ or CaO, to name only a few.

The support materials used may have a specific surface area in the rangefrom 10 to 1000 m²/g, a pore volume in the range from 0.1 to 5 ml/g anda mean particle size of from 0.1 to 10 cm. Preference may be given tosupports having a specific surface area in the range from 0.5 to 500m²/g, a pore volume in the range from 0.5 to 3.5 ml/g and a meanparticle size in the range from 0.5 to 3 cm. Particular preference maybe given to supports having a specific surface area in the range from200 to 400 m²/g, and a pore volume in the range from 0.8 to 3.0 ml/g

The selectivity promoter may be an organic alcohol, ROH, wherein R is aC1-C18 alkyl-, aryl-, or alkenyl-group, that produces non-ionichydrocarbon product from the oxidized-heteroatom feed. The hydrocarbonproduct may be substantially insoluble in the molten caustic and exitsthe outlet region and may be preferred to a reaction system notcontaining a selectivity promoter because the reaction products withcaustics may tend to be organic hydroxides which are substantially inthe ionic form in severely caustic environments and thus may be morechallenging to separate from the caustic without considerable expense.The selectivity promoter may be more preferably an alcohol, a diol, or apolyol and mixtures thereof. Non limiting examples include, but are notlimited to: methanol, benzyl alcohol, ethylene glycol, propylene glycol,glycerol, pinacol, 1,3-propanediol and the like that may producenon-ionic product from the oxidized-heteroatom feed. The non-ionicproduct may be substantially insoluble and/or inert to caustic and exitsthe outlet region and may be more preferred to a reaction systemcontaining ionic products.

In order to provide a reaction system for decreasing the heteroatomcontent (sulfur, nitrogen, vanadium, and nickel), decreasing the TotalAcid Number, and increasing API gravity of heteroatom-containinghydrocarbon feed streams, the reaction system is preferably heated andcomprises a feed inlet region, a reaction region and an outlet region;the reaction region comprises a caustic compound, optionally a mixtureof caustic compounds, and optionally supported on an inert metal oxide,and optionally a molten caustic liquid, and optionally a molten causticmixture; the inlet region receives the hydrocarbon feed independently oras a mixture comprising a oxidized-heteroatom-rich hydrocarbon and aselectivity promoter that combine to contact with the causticcompound(s); wherein the oxidized-heteroatom-rich hydrocarbons reactwith the caustic and selectivity promoter producing substantiallynon-ionic hydrocarbon products that exit via the outlet region with alower heteroatom content than the feed.

The caustic component operatively positioned in the reaction region ofthe system of the present disclosure may be any inorganic compounds thatexhibit basic properties which includes, but is not limited to,inorganic oxides from group IA and IIA elements, inorganic hydroxidesfrom group IA and IIA elements, or optionally mixtures of oxides andhydroxides of group IA and IIA elements, molten hydroxides of group IAand IIA elements, or optionally mixtures of hydroxides of said elements.Presently preferably inorganic oxides or hydroxides from group IA andIIA elements. More presently preferably inorganic hydroxides from groupIA and IIA elements, or optionally mixtures of oxides and hydroxides ofgroup IA and IIA elements. Even more presently preferably moltenhydroxides of group IA and IIA elements, or optionally mixtures ofhydroxides of said elements. Presently most preferably molten NaOH, KOH,or a mixture thereof. Non-limiting examples may include Li₂O, Na₂O, K₂O,Rb₂O, Cs₂O, Fr₂O, BeO MgO, CaO, SrO, BaO, and the like as well as LiOH,NaOH, KOH, RbOH, CsOH, FrOH, Be(OH)₂, Mg(OH)₂, Ca(OH)₂, Sr(OH)₂,Ba(OH)₂, and the like, and their mixtures or molten mixtures thereof.

Optional support components of the reaction region of the reactionsystem of the present disclosure may be any inorganic oxide, inert oractive, such as, for example, a porous support such as talc or inorganicoxides.

Suitable inorganic oxides are oxides of elements of groups 2, 3, 4, 5,13, 14, 15 and 16 of the Periodic Table of the Elements. Examples ofoxides preferred as supports include silicon dioxide, aluminum oxide andalso mixed oxides of the two elements and corresponding oxide mixtures.Other inorganic oxides which can be used alone or in combination withthe abovementioned preferred oxide supports are, for example, MgO, ZrO₂,TiO₂ or CaO, to name only a few.

The support materials used have a specific surface area in the rangefrom 10 to 1000 m²/g, a pore volume in the range from 0.1 to 5 ml/g anda mean particle size of from 0.1 to 10 cm. Preference is given tosupports having a specific surface area in the range from 0.5 to 500m²/g, a pore volume in the range from 0.5 to 3.5 ml/g and a meanparticle size in the range from 0.5 to 3 cm. Particular preference isgiven to supports having a specific surface area in the range from 200to 400 m²/g, and a pore volume in the range from 0.8 to 3.0 ml/g.

Other advantages and features will be apparent from the followingdetailed description when read in conjunction with the attached drawingsincluding the application of the disclosed techniques to streams otherthan diesel, such as, for example, crude oil, bitumen, gas oils,kerosene, transportation fuels, lubricants, and refinery intermediatesand other contaminated hydrocarbon streams containing sulfur and othercontaminants.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosed systems and methods,reference should be made to the flow diagrams of FIG. 1 and theequations of FIG. 2.

DETAILED DESCRIPTION OF THE DISCLOSURE

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in this specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe following specification and attached claims are approximations thatmay vary depending upon the desired properties sought to be obtained bythe present disclosure. At the very least, and not as an attempt tolimit the application of the doctrine of equivalents to the scope of theclaims, each numerical parameter should at least be construed in lightof the number of reported significant digits and by applying ordinaryrounding techniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the disclosure are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contain certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements.

Unless otherwise noted, the term “effective amount,” as used herein,includes that amount of a substance capable of either increasing(directly or indirectly) the yield of the desulfonylation product orincreasing selectivity towards sulfur-free product formation. Unlessotherwise noted, optimum amounts of a given catalyst, heat or steam canvary based on reaction conditions and the identity of other constituentsyet can be readily determined in light of the discrete circumstances ofa given application. Unless otherwise noted, the term “conversion” ormore precisely “percent conversion” (“% conv.”), as used herein,describes the proportion of moles of sulfone converted by thecombination of desulfonylation and deoxygenation reactions relative tosulfone fed into the reaction. Unless otherwise noted, the term“selectivity” as used herein describes the mole percent productsconverted that contain no sulfur. Unless otherwise noted, the term“yield” as used here and describes the mole percent products convertedto a non-ionic hydrocarbon.

Reaction systems and methods for removing heteroatoms fromoxidized-heteroatom-containing hydrocarbon streams and low-heteroatomcontaining hydrocarbon products derived therefrom are disclosed. Anoxidized-heteroatom-rich hydrocarbon feed, such as, for example, oneprovided by the sulfoxidation method and system disclosed inInternational Publication Number WO 2009/120238 A1, to Litz et al., maybe reacted in the reaction system thereby forming substantiallyheteroatom free hydrocarbon products that are readily separated fromeach other by conventional separation methods (i.e. vapor-liquid,liquid-liquid, or adsorption methods). The hydrocarbon products derivedfrom the reaction system and method may be useful as transportationfuels, lubricants, and refinery feeds, refinery intermediates andproducts.

In order to provide a reaction system and method for reducing theheteroatom content and increasing API gravity, decreasing TAN ofoxidized-heteroatom-containing hydrocarbon feed streams, the reactionsystem may be preferably heated and comprises a feed inlet region, areaction region and an outlet region; the reaction region comprises acaustic compound, optionally a mixture of caustic compounds, andoptionally supported on an inert metal oxide, and optionally a moltenliquid, and optionally a molten mixture; the inlet region may receivethe hydrocarbon feed independently or as a mixture comprising asulfone-rich hydrocarbon and a selectivity promoter that combine tocontact with the caustic compound(s); wherein theoxidized-heteroatom-rich hydrocarbons react with the caustic andselectivity promoter producing substantially non-ionic hydrocarbonproducts that exit via the outlet region with a lower heteroatom contentthan the feed.

The caustic component operatively positioned in the reaction region ofthe system of the present disclosure may be any inorganic compounds thatmay exhibit basic properties which includes, but is not limited to,inorganic oxides from group IA and IIA elements, inorganic hydroxidesfrom group IA and IIA elements, or optionally mixtures of oxides andhydroxides of group IA and IIA elements, molten hydroxides of group IAand IIA elements, or optionally mixtures of hydroxides of said elements.Non-limiting examples may include Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, Fr₂O, BeOMgO, CaO, SrO, BaO, and the like as well as LiOH, NaOH, KOH, RbOH, CsOH,FrOH, Be(OH)₂, Mg(OH)₂, Ca(OH)₂, Sr(OH)₂, Ba(OH)₂, and the like, andtheir mixtures or molten mixtures thereof.

Optional support components of the reaction region of the reactionsystem of the present disclosure may be any inorganic oxide, inert oractive, such as, for example, a porous support such as talc or inorganicoxides.

Suitable inorganic oxides may be oxides of elements of groups 2, 3, 4,5, 13, 14, 15 and 16 of the Periodic Table of the Elements. Examples ofoxides preferred as supports include silicon dioxide, aluminum oxide andalso mixed oxides of the two elements and corresponding oxide mixtures.Other inorganic oxides which may be used alone or in combination withthe abovementioned preferred oxide supports may be, for example, MgO,ZrO₂, TiO₂ or CaO, to name only a few.

The support materials used may have a specific surface area in the rangefrom 10 to 1000 m² /g, a pore volume in the range from 0.1 to 5 ml/g anda mean particle size of from 0.1 to 10 cm. Preference may be given tosupports having a specific surface area in the range from 0.5 to 500 m²/g, a pore volume in the range from 0.5 to 3.5 ml/g and a mean particlesize in the range from 0.5 to 3 cm. Particular preference may be givento supports having a specific surface area in the range from 200 to 400m²/g, and a pore volume in the range from 0.8 to 3.0 ml/g.

The selectivity promoter may be an organic alcohol, ROH, wherein R is aC1-C18 alkyl-, aryl-, or alkenyl-group, that produces non-ionichydrocarbon product from the oxidized-heteroatom feed. The hydrocarbonproduct may be substantially insoluble in the molten caustic and exitsthe outlet region and may be preferred to a reaction system notcontaining a selectivity promoter because the reaction products withoutthe promoter tend to be organic hydroxides which are substantially inthe ionic form in severely caustic environments and thus may be morechallenging to separate from the caustic without considerable expense.The selectivity promoter may be presently more preferably an alcohol, adiol, or a polyol and mixtures thereof. Non limiting examples include,but are not limited to: methanol, benzyl alcohol, ethylene glycol,propylene glycol, glycerol, pinacol, 1,3-propanediol and the like thatmay produce non-ionic product from the oxidized-heteroatom feed.Presently more preferred selectivity promoters fall into the class ofcompounds referred to as vicinal diols, which may have hydroxyl groupsbound to adjacent carbon atoms, or the class of alcohols known asprimary alcohols, where the hydroxyl group is bound to a carbon atom,that carbon atom being bound to at most one other carbon atom. Presentlymost preferred may be ethylene glycol or methanol. The non-ionichydrocarbon product may be substantially insoluble and/or inert to thecaustic and exits the outlet region and may be more preferred to areaction system containing ionic products.

FIG. 1 illustrates how the selectivity of the reaction of the presentdisclosure is improved to form more valuable products. Dibenzothiophenesulfone was chosen as a model sulfur compound because most of the sulfurin an average diesel fuel is in the form of substituted or unsubstituteddibenzothiophene. Equation (1) illustrates how hydroxide attacks thesulfur atom of dibenzothiophene sulfone (A), formingbiphenyl-2-sulfonate (B). Equation (2) illustrates how hydroxide mayattack B at the carbon atom adjacent to the sulfur atom, formingbiphenyl-2-ol (C) and sulfite salts (D). Compound C may ionize in basicmedia, and may dissolve in the aqueous or molten salt layer. Equation(3) illustrates how hydroxide may attack the sulfur atom of B to formbiphenyl (E) and sulfate salts (F). Equation (4) illustrates how, in thepresence of a primary alcohol, including, but not limited to, methanol,methoxide ions generated in-situ may attack the carbon atom, formingether compounds, such as 2-methoxybiphenyl (G). Equation (5) illustratesthe reaction of dibenzothiophene sulfone with alkoxides alone, not inthe presence of hydroxide, as taught by Aida et al, to formbiphenyl-2-methoxy-2′-sulfinate salt (H), which may be substantiallysoluble in the caustic. Using aqueous or molten hydroxide without thepresently disclosed selectivity promoter will cause reaction (1) tooccur, followed predominantly by reaction (2). When the vicinal diolselectivity promoter disclosed herein is used, reaction (1) occurs,followed predominantly by reaction (3). When the primary selectivitypromoter (alcohol) disclosed herein is used, reaction (1) occurs,followed predominantly by reaction (4). It can be seen that the hydrogenatoms that become attached to biphenyl come from hydroxide. When wateris used in the regeneration of the caustic, the ultimate source of thehydrogen atoms added to the biphenyl may be water.

Two representative embodiments of a plurality of possible representativeembodiments of the systems and methods for removing contaminants fromhydrocarbon streams and feed contaminated products derived therefrom areshown in FIG. 2. Both systems and methods may begin with aheteroatom-contaminated hydrocarbon feed to be subjected to treatment inorder to meet current and future environmental standards. In onerepresentative system and method, an oxidized-heteroatom-containinghydrocarbon feed may be provided through the line A to a mixing vessel10 through a feed inlet where the contaminated feed may be combined witha caustic and a selectivity promoter where it is allowed to react in themixing vessel 10 to decontaminate the contaminated feed. The reactingcombination may be preferably heated generally in a range of temperaturefrom 50-450 C at a pressure from 0-800 psi.

The mixing vessel 10 may comprise a feed inlet 12, a reaction mixturecomprising an oxidized-heteroatom-containing hydrocarbon streams,caustic, glycol, and reaction intermediates and products, an outlet 14operatively connected to a settler vessel 16, where the cleaned oil(substantially non-ionic hydrocarbon products having a heteroatomcontent less than the oxidized-heteroatom-containing hydrocarbon feedstreams) may be optionally water washed and/or centrifuged 18 to producea substantially heteroatom-free hydrocarbon product 20. The settledcaustic and selectivity promoter can be removed by gravity settling fromthe bottom of settler vessel 16 to a flue gas desulfurization/causticrecovery unit 22. The recovered caustic and selectivity promoter arethen sent back to the mixer vessel 10 to allow for a continuousdecontamination reaction process. The settler vessel 16 may comprise afeed inlet 24 from the mixer 10, a clean oil outlet 26 to an optionalwater wash/centrifuge 18 and then to a clean oil recovery location (notshown) and a caustic/selectivity promoter outlet which may beoperatively connected to a flue gas desulfurization caustic recoveryunit 22. The flue gas desulfurization caustic recovery unit 22 maycomprise a recovered caustic/selectivity promoter outlet 28 which isoperatively connected to the mixer 10 for transporting recoveredcaustic/selectivity promoter from the flue gas desulfurization causticrecovery unit 22 to the mixer 10, providing the continuous processmentioned above. The flue gas desulfurization caustic recovery unit 22may also comprise a gypsum outlet 30 for transporting gypsum to a gypsumstorage or distribution unit (not shown).

In a second representative method and system aoxidized-heteroatom-containing hydrocarbon feed stream may be providedthrough the line B to a continuous countercurrent reaction column (CCRcolumn) 40, at the top of such column, a recovered caustic andselectivity promoter stream are fed thereto the two streams contact eachother in a countercurrent fashion and the selectivity promoter, causticand sulfite exit through an outlet 42 in the bottom of the column 40 andare transported to a flue gas desulfurization caustic recovery unit 22,where the caustic and the selectivity promoter are regenerated andrecovered. The cleaned oil 44 exits from the top of the countercurrentrecovery column where it may be optionally washed with water andcentrifuged to produce a substantially heteroatom-free hydrocarbonproduct.

In both the systems and methods, route A, where employing amixer/settler and route B employing a countercurrent reaction column,generate a used caustic/selectivity promoter stream that exits to theflue gas desulfurization caustic recovery unit 22 to produce aregenerated caustic and selectivity promoter stream that is recycled tothe initial stage of the systems and methods and a gypsum by-productcontaining the heteroatoms previously residing in the untreated feedstream.

EXAMPLES

In order to demonstrate the significant benefit of the presentdisclosure, examples of the systems and methods of the presentdisclosure were performed. For comparative purposes, several controlreactions were performed. The reaction vessel consisted of a stainlesssteel Parr type reactor vessel. The reactor was charged with anoxidized-heteroatom-rich hydrocarbon feed and heated to a temperature of275 C at constant feed rate. The products were analyzed for heteroatomcontent.

Example 1

A stainless steel (type 316) Parr-type pressure reactor with a volume of1000 mL was charged with 29 grams of a 1:1 by moles mixture of sodiumhydroxide and potassium hydroxide, 11 grams of dibenzothiophene sulfone,and 202 grams of 1,2,3,4-tetrahydronaphthalene. The vessel was heatedunder rapid stirring to 300° C. The reactor was held at this temperaturefor 60 minutes, during which the pressure rose to a maximum of 150 psi,then removed from heat and allowed to cool without stirring. 200 gramsof liquid were decanted from the reactor, and 41 grams of solidsremained. The tetralin layer was analyzed by HPLC. The solids wereacidified by adding 125 mL of 5.0M HCl. Vigorous bubbling of releasedsulfur dioxide from the neutralization of sulfites occurred, confirmedby a sulfur dioxide detector. Dichloromethane was added to extractorganics, which was then evaporated, leaving a light brown oil, whichwas analyzed by HPLC. It was found that >99% of the dibenzothiophenesulfone was converted, to the following products: ortho-phenylphenol(56%), biphenyl (21%), dibenzofuran (4%), and dibenzothiophene (4%), fora total sulfur-free yield of 81%. The yield of all organics was 95%.

Examples 2-4

The experiment of EXAMPLE 1 was repeated three times, except that thetemperature was 275° C. The average results were: 94.5% conversion ofdibenzothiophene sulfone, to the following products: ortho-phenylphenol(58%), biphenyl (9%), and dibenzofuran (5%). No dibenzothiophene wasdetected (<1%). The total sulfur-free yield was 73%. The average yieldof all organics was 97%.

Example 5

The experiment of EXAMPLE 2 was repeated except that 20 grams ofmethanol was added to the reactor with the other reactants. The pressurerose to 350 psi during the reaction. It was found that 92% of thedibenzothiophene sulfone had been converted to the following products:2-methoxybiphenyl (40%), ortho-phenylphenol (30%), biphenyl (6%), anddibenzofuran (3%). No dibenzothiophene was detected (<1%). The totalsulfur-free yield was 79%, with 49% being non-ionizable products. Inaddition, sulfur dioxide was detected after the run when the pressurewas vented, before any acid had been added. The yield of all organicswas 97%, not including methanol, which was washed away in the acidworkup.

Example 6

The experiment of EXAMPLE 2 was repeated except that 45 grams oftert-butanol was added. The results were similar to those of EXAMPLE 2,and the expected tert-butyl ether was not detected. Sulfur dioxide wasdetected just after the run cooled. The yield of all organics was 92%.

Example 7

The experiment of EXAMPLE 5 was repeated except that 33 grams of sodiummethoxide was added to the reactor with the other reactants. The resultswere similar to those of EXAMPLE 5.

Example 8

The experiment of EXAMPLE 5 was repeated except that the 29 grams of 1:1molar sodium hydroxide/potassium hydroxide mixture were omitted, and 33grams of sodium methoxide (which contains some sodium hydroxide asimpurity) was added. The results were analyzed by GC-MS, which showedthat conversion of dibenzothiophene sulfone was only ˜80%, and that themajor product formed was ortho-phenylphenol, followed by2-methoxybiphenyl and biphenyl. Sulfur dioxide was detected immediatelyafter the run cooled. The yield of all organics was 90%.

Example 9

The experiment of EXAMPLE 5 was repeated except that the reaction washeld at temperature for 90 minutes. The results were similar to those ofEXAMPLE 5. The yield of all organics was 95%.

Example 10

The experiment of EXAMPLE 5 was repeated except that 60 grams ofmethanol was used. The pressure rose to 750 psi during the reaction. Itwas found that 94% of the dibenzothiophene sulfone had been converted,to the following products: ortho-phenylphenol (54%), dibenzofuran (10%),2-methoxybiphenyl (9%), and biphenyl (8%). No dibenzothiophene wasdetected (<1%). Total sulfur-free yield was 81%. Sulfur dioxide wasdetected just after the run cooled. The yield of all organics was 100%,not counting methanol.

Example 11

The experiment of EXAMPLE 5 was repeated except that 87 grams of the 1:1by moles mixture of sodium hydroxide and potassium hydroxide was used.It was found that 97% of the dibenzothiophene sulfone was converted. Theproduct distribution was similar to that of EXAMPLE 5. The yield of allorganics was 91%.

Example 12

The experiment of EXAMPLE 2 was repeated except that 48 grams of phenolwere added to the reactor along with the other reactants. The pressurereached 200 psi during the run. No sulfur dioxide was detected after therun, nor was any detected when the solids were acidified with HCl. Theproducts were analyzed by GC-MS, which did not detect anydibenzothiophene sulfone. The major products were ortho-phenylphenol anddibenzothiophene. The yield of all organics was 96%.

Example 13

The experiment of EXAMPLE 1 was repeated except that the reactor washeld at temperature for 120 minutes. The results were similar toEXAMPLE 1. The oil layer was decanted from the reactor, and 200 grams ofmethanol was added to the solids. These were sealed and stirred togetherat 60° C. for 5 hours. A sample of this product was extracted withdichloromethane and water, and the dichloromethane layer was analyzed byGC-MS. Only a trace of 2-methoxybiphenyl was detected.

Example 14

The experiment of EXAMPLE 2 was repeated except that 40 grams ofdicyclopentadiene was added to the reactor with the other reagents. Thesample was analyzed by GC-MS, which showed a large number of differentproducts, including a substantial amount of dibenzothiophene.

Example 15

The 1 L pressure reactor was charged with 200 grams of ethanol, 2.4grams magnesium turnings, and 11 grams dibenzothiophene sulfone. Themixture was stirred at room temperature for 60 minutes. The product wasanalyzed as-is by GC-MS. Approximately 25% of the dibenzothiophenesulfone had been converted, and the only product was dibenzothiophene.

Example 16

The experiment of EXAMPLE 5 was repeated except that only 10 grams ofmethanol was added to the reactor with the other reagents. The productwas worked up similar to EXAMPLE 1. It was found that 97% of thedibenzothiophene had been converted, to the following products:ortho-phenylphenol (15%), dibenzofuran (2%), 2-methoxybiphenyl (47%),and biphenyl (8%), dibenzothiophene (2%). Total sulfur-free yield was72%. Sulfur dioxide was detected just after the run cooled. The yield ofall organics was 97%, not counting methanol.

Example 17

A 1 L Parr pressure reactor was charged with 200 grams of tetralin, 12grams sodium hydroxide, 17 grams potassium hydroxide, 11 gramsdibenzothiophene sulfone, and 28 grams ethylene glycol. The reactor waspurged with nitrogen prior to the run, until no oxygen could be detectedon an oxygen sensor (<0.1%). The reactor was sealed and heated to 275°C. for one hour. The product was worked up by the procedure inEXAMPLE 1. However, no sulfur dioxide was detected after the run, orduring the acidification. Also, very few bubbles formed during theacidification step. It was found that 100% of the dibenzothiophenesulfone had been converted, to the following products: biphenyl (>75%),ortho-phenylphenol (<25%). The total sulfur-free yield was 100%. Theyield of all organics was 97%, not counting ethylene glycol, which waswashed away in the acid workup.

Example 18

The experiment of EXAMPLE 17 was repeated except that in place oftetralin and dibenzothiophene sulfone, 100 grams of anoxidized-heteroatom-containing diesel stream with ˜2000 ppm sulfur inthe form of sulfones was used. In addition, 1.5 grams sodium hydroxide,2.2 grams potassium hydroxide, and 3.2 grams ethylene glycol were added.The oil product was washed with water and dried, then analyzed forsulfur content by XRF. The process was repeated a total of three times.The sulfur content of the fuel was significantly reduced, to less than430 ppm S. The nitrogen content was decreased by at least 85%, and thetotal acid number was decreased below measurable concentrations, atleast a 60% decrease.

Example 19

The experiment of EXAMPLE 18 was repeated except that a bitumen streamcontaining ˜4% sulfur was used in place of a diesel. The sulfur contentafter the reaction was significantly reduced, to less than 1.75% wtsulfur.

Example 20

A stainless steel 1 L Parr-type reactor was charged with 100 grams of anoxidized-heteroatom-containing 2.75% wt sulfur bitumen oil, 21 gramssodium hydroxide, 29 grams potassium hydroxide, and 64 grams ethyleneglycol. The reactor was purged with nitrogen, then heated to 275 degreesC. and held at that temperature for 1 hour, then cooled. The oil waswashed with water to remove caustic and ethylene glycol until the pH ofthe water wash was below 8.5, then dried. The sulfur content after thereaction was at most 1% sulfur, vanadium content had been reduced from175 ppm to less than 65 ppm, and nickel content had been reduced from 67ppm to below 33 ppm.

Prophetic Example 1

A stainless steel (type 316) Parr-type pressure reactor with a volume of1000 mL is charged with about 11 grams of dibenzothiophene sulfone,about 202 grams of 1,2,3,4-tetrahydronaphthalene, about 24 g of benzylalcohol and about 5.7 g of potassium hydroxide. The vessel is heatedunder rapid stirring to 195° C. The reactor is held at this temperaturefor about 60 minutes, and then it is removed from the heat and allowedto cool without stirring. About 210 grams of liquid are decanted fromthe reactor, and about 8 grams of solids remain. The tetralin layer isanalyzed by HPLC. The solids are acidified by adding about 25 mL ofabout 5.0M HCl. Sulfur dioxide is released as the neutralization ofsulfites occurs. Dichloromethane is added to extract organics, which arethen evaporated, leaving an oil, which is analyzed by HPLC. Theconversion of dibenzothiophene sulfone is at least as good as thatpresented in EXAMPLE 5 with a similar product distribution:2-benzyloxy-biphenyl (about 40%), ortho-phenylphenol (about 30%),biphenyl (about 6%), and dibenzofuran (about 3%).

Prophetic Example 2

A stainless steel (type 316) Parr-type pressure reactor with a volume of1000 mL is charged with about 200 grams of bitumen oil having a sulfurcontent of 2% wt, 15 grams sodium hydroxide, 21 grams potassiumhydroxide, and 35 grams ethylene glycol. The vessel is heated underrapid stirring to 275° C. The reactor is held at this temperature forabout 60 minutes, and then it is removed from the heat and allowed tocool without stirring. About 200 grams of liquid are decanted from thereactor, and about 70 grams of solids remain. The removal of sulfur andmetals is at least as good as that presented in EXAMPLE 18 and EXAMPLE20. Sulfur content is decreased to less than 1% wt, nitrogen and metalscontent is decreased by more than 50%. The API gravity of the feed isincreased by at least 5 units.

The results of the above examples are illustrated in the following table1.

EXAMPLE % 2-methoxy- ortho- dibenzo- dibenzo- # Conversion biphenylphenylphenol biphenyl furan thiophene 1 99% 0% 56% 21% 4% 4% 2 95% 0%58% 9% 5% 0% 3 95% 0% 58% 9% 5% 0% 4 95% 0% 58% 9% 5% 0% 5 92% 40% 30%6% 3% 0% 6 95% 0% 58% 9% 5% 0% 7 92% 40% 30% 6% 3% 0% 8 ~80%   major 992% 40% 30% 6% 3% 0% 10 94% 9% 54% 8% 10% 0% 11 92% 40% 30% 6% 3% 0% 12N/A major 13 99% 0% 56% 21% 4% 4% 14 N/A major 15 N/A major 16 97% 47%15% 8% 2% 2% 17 100%  0% 25% 75% 0% 0%

While only certain embodiments have been set forth, alternatives andmodifications will be apparent from the above description to thoseskilled in the art such as the application of the disclosed techniquesand apparatus to crude oil, bitumen, kerosene and other fuel streams andthe use of similar reagents for convertingoxidized-heteroatom-containing hydrocarbons s to non-ionic hydrocarbonproducts. These and other alternatives are considered equivalents andwithin the spirit and scope of this disclosure and the appended claims.

1. A reaction system for reducing a heteroatom content, reducing a totalacid number, and increasing API gravity of anoxidized-heteroatom-containing hydrocarbon feed stream comprising: anoxidized-heteroatom-containing hydrocarbon feed stream; and a causticand a selectivity promoter operatively positioned in a contact regionwherein the oxidized-heteroatom -containing hydrocarbon feed streamcontacts the caustic and selectivity promoter thereby producingsubstantially non-ionic hydrocarbon product having a heteroatom contentless than the original oxidized-heteroatom-containing hydrocarbon feedstream.
 2. The reaction system of claim 1, wherein the selectivitypromoter is methanol.
 3. The reaction system of claim 1, wherein theselectivity promoter is ethylene glycol.
 4. The reaction system of claim1, wherein the selectivity promoter is a polyol.
 5. A reaction methodfor reducing a heteroatom content, reducing a total acid number, andincreasing API gravity of an oxidized-heteroatom-containing hydrocarbonfeed stream comprising: providing oxidized-heteroatom-containinghydrocarbon feed streams through a feed inlet region; providing acontact region, the contact region having a molten mixture of sodiumhydroxide and potassium hydroxide and a polyol operatively positionedtherein; contacting the oxidized-heteroatom-containing hydrocarbon feedstream in the contact region thereby producing substantially non-ionichydrocarbon product having a heteroatom content less than theoxidized-heteroatom-containing hydrocarbon feed stream that enteredthrough the inlet region; reducing a total acid number, and increasingAPI gravity; and removing the substantially non-ionic hydrocarbonproducts from the feed stream.
 6. The reaction method of claim 5,wherein the contact region has a molten mixture of sodium hydroxide andpotassium hydroxide and a polyol.
 7. A reaction method for reducing aheteroatom content, reducing total acid number, and increasing APIgravity of oxidized-heteroatom -containing hydrocarbon feed streamcomprising: providing oxidized-heteroatom -containing hydrocarbon feedstream through a feed inlet region; providing a contact region, thecontact region having at least one caustic and a selectivity promoteroperatively positioned therein, wherein the selectivity promoter is apolyol; contacting the oxidized-heteroatom-containing hydrocarbon feedstream in the contact region thereby producing substantially non-ionichydrocarbon product having a heteroatom content less than theoxidized-heteroatom-containing hydrocarbon feed stream that enteredthrough the inlet region; and removing the substantially non-ionichydrocarbon product having a heteroatom content less than theoxidized-heteroatom-containing hydrocarbon feed stream that enteredthrough the inlet region from the contact region to an outlet region. 8.The method of claim 7, wherein the inlet region receives theoxidized-heteroatom-containing hydrocarbon feed stream independently oras a mixture comprising oxidized-heteroatom-containing hydrocarbon feedstream and a selectivity promoter, wherein the oxidized-heteroatomcontaining hydrocarbon feed stream combine with the selectivity promoterto contact the at least one caustic compound wherein theoxidized-heteroatom-containing hydrocarbon of the feed stream react withthe at least one caustic compound and the selectivity promoter such thatthe substantially non-ionic hydrocarbon product having a heteroatomcontent less than the oxidized-heteroatom-containing hydrocarbon feedstream that entered through the inlet region are produced thereby. 9.The method of claim 6, wherein the at least one caustic compoundcomprises: a mixture of caustic compounds.
 10. The method of claim 8,wherein the mixture of caustic compounds is supported on an inert metaloxide.
 11. The method of claim 8, wherein the mixture of causticcompounds is at least one of a molten liquid and a molten mixture. 12.The method of claim 6, wherein the caustic component of the reactionregion comprises: Li₂O, Na₂O, K₂O, Rb₂O, Cs₂O, Fr₂O, BeO MgO, CaO, SrO,BaO, and the like and their mixtures or molten mixtures thereof.
 13. Themethod of claim 6, wherein the caustic component of the reaction regioncomprises: LiOH, NaOH, KOH, RbOH, CsOH, FrOH, Be(OH)₂, Mg(OH)₂, Ca(OH)₂,Sr(OH)₂, Ba(OH)₂, and or mixtures thereof.
 14. The method of claim 6further comprising: a support component; wherein the support componentis at least one of an inert or active inorganic oxide and a poroussupport selected from the group comprising talc or inorganic oxides.